Function isBase64Image

isBase64Image(
    str?: string,
): str is
    | `data:image/gif;base64,${string}`
    | `data:image/jpeg;base64,${string}`
    | `data:image/jpg;base64,${string}`
    | `data:image/png;base64,${string}`
    | `data:image/svg+xml;base64,${string}`
    | `data:image/webp;base64,${string}`
check of the provided string is a base64 string, by simply observing if it starts with "data:image/".
Parameters
- Optionalstr: string
Returns str is
    | `data:image/gif;base64,${string}`
    | `data:image/jpeg;base64,${string}`
    | `data:image/jpg;base64,${string}`
    | `data:image/png;base64,${string}`
    | `data:image/svg+xml;base64,${string}`
    | `data:image/webp;base64,${string}`
- Defined in work/kitchensink_ts/kitchensink_ts/src/image.ts:68